In the News

This roundup summarizes some notable recent items about scientific research, selected from news reports compiled in Sigma Xi’s free electronic newsletters Science in the News Daily and Science in the News Weekly. Online: sitn.sigmaxi.org and www.americanscientist.org/sitnweekly

Live Long with Strong Hearts

If you are an older adult, and your parents lived to be 100 or older, you are likely to be healthier than other adults your age and have decreased risk of a heart attack, stroke, diabetes or death from any other cause, a recent study reports. You will, however, have the same risk of other diseases, such as hypertension, cancer and glaucoma. The results add support to the idea that a predisposition for a longer lifespan could be inherited, maybe in large part due to a lower tendency for cardiovascular disease. It’s hard to say if the longevity is due to family genetics or to healthy habits acquired from parents in childhood, but the most likely explanation is that it’s a combination of both factors.

Today more than 4,000 different minerals exist on Earth. But when the planet formed, few existed. Some 1,500 likely formed before life evolved, from processes such as volcanic explosions. But after that point, life and minerals evolved in tandem. Animals’ shells and bones formed calcite, and plants produced acids around their roots that converted volcanic minerals into clay and soils. Microbes are making new minerals all the time. Knowing which minerals depend on life to be present could be key to the study of other planets.

Although Neanderthals are thought to have grown quickly, they may have reached sexual maturity later and had longer life spans than was previously realized. Studying the skulls of Neanderthal babies revealed that their brains expanded faster in the first few years of life. This resulted in larger adult brain sizes but not earlier completion of brain growth. Large brains growing at high rates require large, late-maturing mothers. It’s therefore possible that modern humans outpaced Neanderthals in breeding.

Ponce de León, M. S., et al. Neanderthal brain size at birth provides insights into the evolution of human life history. Proceedings of the National Academy of Sciences 105:13764–13768 (September 16)

Seeing Exoplanets

The best photographic evidence of planets orbiting other stars captures the subtle crawl of planets as they trace out their paths. Two new planetary systems were imaged in the Milky Way, one of which offers the first glimpse of a system with multiple planets. The team used a technique called adaptive optics, which produces clearer images by compensating for distortions created by Earth’s atmosphere. Direct imaging allows astronomers to detect planets orbiting at much greater distances from their stars. The trio of newly-discovered planets seems to orbit in a plane, suggesting they formed from a debris disk around the star.

Many surfaces repel water, but there are no known natural surfaces that repel oil. Oil’s lower surface tension means that it does not tend to pull itself into droplets but spreads across a surface more readily. To repel any liquid, a material needs to have low surface energy and to be textured, to make liquids bead up and roll away. New materials that look like a forest of microstructures support droplets of oil in the same way that a bed of nails holds up a circus performer. The size, shape and spacing of the microstructures are crucial in their performance. Such materials may make for self-cleaning coatings on paints, windows or solar panels.

An inch-long sea slug is able to take the chloroplasts from the algae it eats and use them to photosynthesize for itself. Young slugs fed with algae for two weeks could survive the rest of their year-long lives without eating. But the chloroplasts only contain enough DNA to encode about 10 percent of the proteins they need to work; the other necessary genes are found in the algae’s nuclear DNA. It turns out that the sea slug has also stolen those genes from the algae, and now has them as a permanent part of its DNA. The genes were even found in the animal’s sex cells, so it can pass the gene, and the ability to keep chloroplasts working, to its offspring. Researchers do not yet know how the slug is able to accomplish such wholesale incorporation of foreign genes. Although genes are known to jump from one species to another, the DNA does not normally appear to function in the new species.

A relatively simple sugar, called glycolaldehyde, has been found in a hospitable area of the Milky Way galaxy, where planets orbiting newly formed stars are expected to exist. The sugar had previously been found toward the galactic center in 2000, but the extreme conditions there made it unclear whether the molecule could form in the rest of the galaxy. This sugar can react to form ribose, a key constituent of RNA. Researchers trained radio telescopes on a large star-forming region about 26,000 light years away and found several radio and microwave signatures of the presence of glycolaldehyde that could be a few hundred thousand years old.